Heat and deformation effects of coal during adsorption and desorption of carbon dioxide

•A novel thermodynamic method based on heat and deformation effects is proposed to study the energy conversion during adsorption and desorption.•A corresponding experimental apparatus that determines temperature and deformation effects simultaneously is developed.•The principle of heat and deformation effects at microscopic and macroscopic levels is presented.

Heat and deformation effects of coal during adsorption and desorption of gases are important to carbon dioxide sequestration and enhanced coalbed methane exploitation. From the perspective of energy conversion, the thermodynamic theory is promising for studying heat and deformation effects. To determine the heat and deformation effects simultaneously, we developed a corresponding experimental apparatus. The adsorption at a constant injection pressure is reversible to desorption under the same initial pressure, as well as the heat and deformation effects. Based on the experimental and molecular simulation results, we present the principle of heat and deformation effects at microscopic and macroscopic levels. The adsorption of carbon dioxide enables the conversion of surface energy to adsorption heat, which causes the temperature to increase, thereby resulting in swelling deformation.

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